[copperpen]

Air brakes can work with either a triple valve or a distributor. Looking through the various CS files that cover the OR air brake system there are no tokens for the distributor operation thus these do not work if used in a wag or eng file.

The missing items are

BrakeDistributorFullServicePressure
BrakeDistributorEmergencyApplicationPressure
BrakeDistributorMaxAuxilaryResPressure
BrakeDistributorEmergencyResPressure
BrakeDistributorReleaseRate
BrakeDistributorApplicationRate
BrakeDistributorEmergencyApplicationRate
BrakeDistributorTrainPipeAuxResPressureDifferenceForApplication
BrakeDistributorTrainPipeControlRatio
BrakeDistributorNormalFullReleasePressure

All of these come from the MSTS loadstr.hdr file. I think these are the missing link in the EP braking system which is currently dysfunctional.

[gpz]

EP is fully functional, but it uses the same configuration tokens as the non-EP brakes. As far as I know, MSTS also uses these tokens, and noone tested out how MSTS behaves when both the original ones and the ones you mentioned are present. So I think, for making things simpler, the original brake code author decided to omit using the BrakeDistributor* tokens.

Just an explanation: for OR there is no need for multiple tokens configuring the same values, since EP brake code is inherited from twin pipe brake system. In case there are multiple MSTS tokens in use, OR needs to decide which one will be the valid configuration, if both are present.

[Lindsayts]

gpz, on 16 July 2015 - 08:54 AM, said:

EP is fully functional, but it uses the same configuration tokens as the non-EP brakes. As far as I know, MSTS also uses these tokens, and noone tested out how MSTS behaves when both the original ones and the ones you mentioned are present. So I think, for making things simpler, the original brake code author decided to omit using the BrakeDistributor* tokens.

Just an explanation: for OR there is no need for multiple tokens configuring the same values, since EP brake code is inherited from twin pipe brake system. In case there are multiple MSTS tokens in use, OR needs to decide which one will be the valid configuration, if both are present.

Hope you do not mind a question!

How can EP brakes be fully functional when the use the same config tokens as BrakeDistrubutor tokens. Now GraduatedReleaseTripleValve works and that effectively is a distributor.

The EP brake problem goes back to the method the system uses to transfer the brake signal, a GraduatedReleaseTripleValve uses the brake pipe and the brake signal speed is the speed of sound in compressed air (from memory this in the order of 1500 to 1800ft/sec), where as EP brakes the signal is electrical (Note 1). The main use if such a system appears to be in suburban electrical (metro) systems where braking is used a great deal.
I believe it would be difficult to pick the difference in performance in say a 6 car pass between the two systems, the propergation delay down a an airline through such a train only being around 1/3rd of a sec. So the difference is stopping distance will only be around 30 ft, where as a normal braking distance for a metro system from 100kph would be around 1000 to 1200ft. So where only looking at a 3 or 4% improvement.

Note 1: just to be complete the speed of an electrical signal depends on the cable constructuon and is usually around 500 to 700 ft/usec, this is around 2/3rds of the speed of light.

Lindsay

[gpz]

EP brake is actually an "upgrade" only to a twin pipe system. Only two extra subcomponents are added:

1) An apply valve, that fills the brake cylinder directly from MR pipe, and
2) A holding valve, that prevents releasing air by triple valve in case of an application, where temporarily the brake cylinder pressure is higher, than it would be by the triple valve's own logic, since the "apply valve" fills it faster, and recognizing this, the triple valve would release the extra pressure by its own.

I think the latter one was implemented incorrectly, that prevented proper graduated releasing.
If of an EP brake electronic line failure, the whole system falls back to a normal twin pipe system. This may happen e.g. in case of a locomotive power cut. OR can also simulate this falling-back, although it is not currently triggered by anything, AFAIK.

Hope this answers your question.

[copperpen]

A bit pointless saying that EP brakes work then because an EP system labelled as such does not. It does not show EP in the brake information page and no pressure is applied to the brake cylinders if using the Distributor tokens. Air twin or single pipe works very well.

The later EP systems also used a distributor, not a triple valve, and the latest versions do not have a main res either. That function is performed by the train brake pipe.

[gpz]

copperpen, on 16 July 2015 - 11:47 AM, said:

A bit pointless saying that EP brakes work then because an EP system labelled as such does not. It does not show EP in the brake information page and no pressure is applied to the brake cylinders if using the Distributor tokens. Air twin or single pipe works very well.

I'm sorry, I cannot follow you, what you mean as pointless. EP does show in the brake information page (provided you used "EP" as BrakeSystemType), and pressure is applied as well. It is your configuration is incorrect, if I understood, and as explained in the other thread.

copperpen, on 16 July 2015 - 11:47 AM, said:

The later EP systems also used a distributor, not a triple valve, and the latest versions do not have a main res either. That function is performed by the train brake pipe.

OR also uses a "distributor", which is actually a triple valve, with ability of graduated release. There is a bug here, as I also explained. I think you wanted to write "the older versions do not have a main res either", don't you? But I'm not sure there were such versions.

[copperpen]

gpz, on 16 July 2015 - 12:14 PM, said:

I'm sorry, I cannot follow you, what you mean as pointless. EP does show in the brake information page (provided you used "EP" as BrakeSystemType), and pressure is applied as well. It is your configuration is incorrect, if I understood, and as explained in the other thread.


OR also uses a "distributor", which is actually a triple valve, with ability of graduated release. There is a bug here, as I also explained. I think you wanted to write "the older versions do not have a main res either", don't you? But I'm not sure there were such versions.

It matters not what I use in the brake control data section. If I use EP or EP_twin_pipe or EP_single_pipe in the BrakeSystemType line, There is only a - in the type column of the Brake Information page and zero brake cylinder pressure. If I use Air instead of EP, then everything works. Brake cylinder pressure that varies according to how far the brake handle is applied

How about publishing a working EP brake system. EDIT. Found the missing link. BrakeEquipmentType must read as EP_Brake. BrakeSystemType as EPEverything else then falls into place, the only thing wrong is the 2P shown instead of EP in the brake information page. No need to go looking for a partial release bug. it all works.

[gpz]

I have just tried, and it works. Double and triple-check, if your BrakeSystemType is set exactly to "EP".

[gpz]

copperpen, on 16 July 2015 - 12:30 PM, said:

the only thing wrong is the 2P shown instead of EP in the brake information page. No need to go looking for a partial release bug. it all works.

Then something is still wrong, I'm afraid. If EP is recognized, then EP must be the keyword indicated in HUD. 2P means you are still running a twin pipe system, where the partial release bug is not present, only true EP is affected.

[gpz]

copperpen, on 16 July 2015 - 12:30 PM, said:

BrakeEquipmentType must read as EP_Brake.

I'm surprised about this too, since I cannot find anything in code that would parse "EP_Brake". Actually you may omit this info entirely.